There are a huge number of microorganisms in the sea, including a plenty of unexploited new species and new gene resources. With the development of technology, exploitation of marine microbial resources has become a research hotspot all over the world. However, owing to the difficulties in sampling and cultivating, the exploitation and utilization of marine microbial and their genetic resources is still limited. Mining new genes and studying their functions is of great significance for the exploitation and utilization of marine microbial resources.
Cyclic nucleotides are important second messengers in living cells, involving in a range of intracellular physiological pathways. It was found that 3′,5′-cAMP, 3′,5′-cGMP, 3′,5′-cCMP, 3′,5′-cUMP, c-di-GMP, c-di-AMP and cGAMP are all second messengers to regulate intracellular signaling pathways. In addition, 2′,3′-cAMP are found in human kidney cells and mammal brain cells, 2′, 3′-cAMP and 2′, 3′-cGMP in plant cells, and 2′, 3′-cCMP and 2′, 3′-cUMP in Pseudomonas fluorescens. Recent studies showed that these four kinds of 2′, 3′-cNMPs are likely a new type of second messengers. Due to the important physiological roles they may play, 2′, 3′-cNMPs have attracted more and more attention, and therefore, there will be an increasing demand of 2′, 3′-cNMPs in scientific research and pharmaceutical application. So far, all available 2′, 3′-cNMPs are chemically synthesized. However, chemical synthesis have disadvantages such as low yield and high price, which limit the application of 2′,3′-cNMPs to some extent.